Railway car cushioning mechanism

ABSTRACT

A railway car construction according to the present invention, includes an underframe having a longitudinally disposed center sill that is of hollow construction and has a transverse structural wall spaced from the extremity thereof. An aperture is formed in the transverse structural wall and receives a connecting member of a primary cushioning mechanism disposed within the center sill outwardly of the transverse structural wall. A draft cushioning mechanism is disposed within the center sill inwardly of the transverse structural wall and is secured to the connecting member. The draft cushioning mechanism functions only to cushion draft loads that are applied to the primary cushioning mechanism. Draft stops are retained in assembly with the center sill to limit compression of the draft-cushioning mechanism and to transfer excessive draft forces directly into the center sill structure.

United States Patent [72] Inventors Eula R. Atkinson Conroe; Richard G. Powell, Houston, both of Tex. [2i 1 Appl. No. 26,475 [22] Filed Apr. 8, 1970 [45 Patented Nov. 23, 197i [731 Assignee ACF Industries, Incorporated New York,-N.Y.

[54] RAILWAY CAR CUSHIONING MECHANISM 13 Claims, 4 Drawing Figs. 52] US. Cl 213/46, 213/8, 213/43 [5]] lnt.Cl B6lg9/l4 [50] Field oiSearch 2l3/8,43. 46, 47

[56] References Cited UNITED STATES PATENTS 2,635,766 4/l953 Willison 213/46 R 3,378,149 4/l968 Powell .Q

ABSTRACT: A railway car construction according to the present invention, includes an underframe having a longitudinally disposed center sill that is of hollow construction and has a transverse structural wall spaced from the extremity thereofv An aperture is formed in the transverse structural wall and receives a connecting member of a primary cushioning mechanism disposed within the center sill outwardly of the transverse structural wall. A draft cushioning mechanism is disposed within the center sill inwardly ofthe transverse structural wall and is secured to the connecting member. The draft cushioning mechanism functions only to cushion draft loads that are applied to the primary cushioning mechanism. Draft stops are retained in assembly with the center sill to limit compression of the draft-cushioning mechanism and to transfer excessive draft forces directly into the center sill structure.

BACKGROUND OF THE INVENTION This invention relates generally to cushioned railway cars and more particularly to oleopneumatic type hydraulic cushioning mechanisms having draft cushioningcapability.

Railway cars are frequently subjected to buff and draft impact forces thatmay result when the cars are humped" at a classification yard or may result during theoccurrence of train action that is developed when trains change speed or when a train is being operated in areas where steep grades occur. In order to substantially reduce the severity of draft and buff impact forces for protection of the railway car structure and its lading from damage, railway carsare frequentlyprovided with cushioning mechanisms. Oleopneumatic-cushioning mechanisms are frequently utilized for railway I car cushioning and may-have only a bufi forcecushioning capability or may include the capability both buff and draft forces. As is usually the case, however, oleopneumatiec'ushioning mechanisms that include draft force cushioning capability generally are limited in the magnitude of draft forces that may be efi'ectively cushioned. Moreover, draft cushioning in such mechanisms is frequently only available in the compressed condition of the cushioning mechanism. In the event the cushioning mechanism is fully extended, there frequently is no draft-cushioning capability available in the primary cushioning mechanism.

In order to provide draft-cushioning capability in the fully extended condition of the primary oleopneumatic cushioning mechanism, frequently a resilient draft package is cooperatively added to the cushioning mechanism, such as illustrated in U.S. Pat.'No. 3,378,149. Structures of this nature, however, are generally limited to installation from the bottom of the car, thereby eliminating field-servicing capability because the truck must be separated from the car in order to allow installation of 'the cushioning mechanism. It would be desirable to provide buff and draft force cushioning systems that may be installed from the end of the car or from the bottom of the car as desired to allow optimum flexibility of car design.

SUMMARY OF THE INVENTION It is, therefore, a principle object of the present invention to provide a novel cushioned railway car construction having effective cushioning capability, both in buff and draft.

It is another important object of the present invention to provide a novel cushionedrailway car construction having a draft-cushioning mechanism capable of absorbing draft forces and being protected by cooperating structure against damage by excessively high draft forces.

Among the several objects of the present invention is noted the contemplation of a novel cushioned railway car construction having a primary cushioning mechanism having draftcushioning capability and having a secondary draft-cushioning mechanism that acts only in draft and cooperates with the primary cushioning mechanism in draft to achieve smooth force transition.

It is still another object of the present invention to provide a novel cushioned railway car construction, including a draftcushioning mechanism that maybe removed and installed without necessitating removal of the primary cushioning buff and draft force cushioning mechanism that is simple in nature, reliable in use and low in cost.

The above and other objects and novel features of the instant invention will be readily apparent from the following description taken in conjunction with the accompanying drawings. It is to be expressively understood that the drawings are provided for the purpose of illustration and are not intended to define the limits of the invention, but rather to merely illustrate preferred embodiments and structures incorporating the features of the instant invention. Such description will be referred to by reference characters in the drawings in which:

FIG. 1 is a fragmentary plan view illustrated partially in section showing the center sill structure of a railway car underframe including a buff and draft force-cushioning mechanism constructed in accordance with the present invention and showing the cushioning mechanism in the neutral position thereof.

FIG. 2 is a fragmentary plan view illustrated partially in section showing the center sill and cushioning mechanism of FIG. I with the'draft-cushioning mechanism shown in the fully compressed condition thereof.

FIG. 3 is a fragmentary plan view of the center sill portion of a railway car underframe and-a buff and draft force-cushioning mechanism constituting a modified embodiment of the present invention and showing the cushioning mechanism in the neutral position thereof.

FIG. 4 is a fragmentary plan view of the center sill and cushioning mechanism of FIG. 3 illustrating the modified draft-cushioning mechanism in the fully compressed condition thereof.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings for a detailed description of the present invention, in FIGS. 1 and 2 is generally illustrated one extremity of a center sill 10 comprising a portion of a railway car underframe. The center sill l0includes side flanges l2 and 14 that are fonned integral with vertical webs l6 and 18,respectively. The vertical webs areintegrally connected to mechanism; thereby further'promoting field serviceability of the car-cushioning system.

It is another object of the present invention to provide a novel cushioned railway car construction having an oleopneumatic type primary cushioning mechanism having a draftcushioning system therein and a separate resilient draftcushioning mechanism that cooperates with the draft-cushioning capability beyond the limits of the draft-cushioning system and to prevent undue wear of the draft-cushioning system.

It is an even further object of the present invention to provide a novel cushioned railway car construction, including a a horizontal web, not shown, to define a generally hat-shaped structure for the center sill construction. A backstop structural element 20, is disposed within the center sill and is connected to the side webs and top web by welding or the like. The backstop structuralelement20 defines an oversolid stop 22 that is engaged by the outer cylinder structure of a cushioning mechanism in the manner discussed hereinbelow in order to prevent the cushioning mechanism from being damaged by the application of excessively high buff forces thereto. The backstop structural element also includes an integral transverse structural partition 24, having an aperture 26 formed centrally therethrough.

The backstop structural element 20 is spaced from the extremity of the center sill in order to define a receiving chamber 28 for an oleopneumatic primary cushioning mechanism illustrated generally at 30. The primary cushioning mechanism includes an outer cylinder 32 and an inner cylinder 34 that are movably assembled in telescopic relation and cooperate with an orifice plate 36 to define inner and outer hydraulic chambers 38 and 40. Metering of hydraulic fluid between the variable volume fluid chambers, 38 and 40, is achieved through a metering orifice 42 under control of a tapered metering pin 44, carried by an outer cylinder end cap 46, forming a closure for the outer cylinder 32. A free piston 48 is disposed within the inner cylinder, 34, separating the inner hydraulic chamber 38 from a pneumatic chamber 50, that is preloaded with a gas such as air or dry nitrogen to a preload pressure that is capable of achieving recentering of the primary cushioning mechanism to the fully extended or neutral condition thereof, subsequent to compression by impact forces. The outer cylinder endcap 46 and a packing retainer member 52, are secured into assembly with the outer cylinder 32 by a plurality of tie bolts 54.

The inner cylinder 34 is provided with an inner cylinder end cap 56, having a connecting rod 58 formed integrally therewith and extending through the aperture 26 in the transverse structural partition 24. A draft-cushioning mechanism illustrated generally at 60, is disposed within the center sill construction inwardly of the transverse structural partition 24 and is received about the connecting stem 58. The draft-cushioning mechanism 60 comprises a bearing plate 62 that is disposed in contact with structural webs 64 formed integrally with the transverse structural partition. Aplurality of resilient pads 66, separated by metal plates 68 are interposed between the bearing plate 62 and a retainer plate 70. A nut member 72 is threadedly received by the connecting stem 58 and biases the retainer plate 70 into engagement with the resilient pads in such manner as to develop a predetermined mechanical preload pressure in the draft-cushioning mechanism.

Application of evenly distributed bufi forces into the transverse structural partition 24 is assured by a force alignment plate 74, interposed between the end cap 56 and the transverse structural partition 24 and providing a convex semispherical surface 76 that is disposed in mating engagement with a concave semispherical surface 78, defined by the end cap. Even though the primary cushioning mechanism may be slightly misaligned within the center sill structure, the universal connection defined by cooperation of the plate 74 with the end cap 56 assures evenly distributed force application to the transverse structural partition 24.

The outer cylinder end cap 46 is provided with a blind coupler opening 80 in which is disposed the shank portion 82 of a car coupler 84. A transverse coupler key 86 is received within registering openings 88 and 90 and 92, formed in the outer cylinder end cap and coupler shank to retain the coupler in assembly with the outer cylinder end cap. A pair of vertical draft stop lugs 94 and 96, are retained within vertical slots 98 and 100, respectively, formed in the center sill structure and cooperating with the horizontal key 86 in such manner as to prevent the key 86 from becoming disassembled fon'n the end cap and coupler shank openings. The draft stop lugs 94 and 96 present stop surfaces 102 and 104, respectively, that are disposed to engage stop shoulders 106 and 108, provided on the outer cylinder end cap 46, upon maximum compression of the draft-cushioning mechanisms 60. The draft stop lugs 94 and 96 illustrated in FIGS. 1 and 2 are removable to allow insertion and removal of the primary cushioning mechanism from the end of the center sill thereby promoting field serviceability of the cushioning system. FIGS. 3 and 4, however, illustrate a modified embodiment of the present invention including a primary cushioning mechanism that is installed from the bottom of the center sill structure. The invention may be effectively utilized therefore without placing undue limits on design of the car structure.

As illustrated in FIG. 1, the draft-cushioning mechanism 60 and the primary hydraulic cushioning mechanism 30 are disposed in their neutral positions, thereby causing the shoulders 106 and 108 of the outer cylinder end cap to be disposed in spaced relation with the corresponding stop surfaces 102 and 104. As illustrated in FIG. 2, the resilient draft-cushioning mechanism 60 has been fully compressed by a draft load applied to the coupler 84, thereby moving the shoulders 106 and 108 of the outer cylinder end cap into abutting relationship with stop surfaces 102 and 104. Under this condition, excessive draft load forces will be transmitted directly from the coupler through the outer cylinder end cap and to the center sill structure through the draft stop lugs, 94 and 96. The resilient draft-cushioning mechanism 60, therefore, cannot be overcompressed by excessive draft forces thereby assuring extensive service life thereof.

The primary hydraulic cushioning mechanism 30 is provided with a variable volume draft-cushioning chamber 110 that is defined between the cylinders 32 and 34 and is disposed in fluid communication with the inner hydraulic chamber 38 through a plurality of orifices 112. A draft-cushioning valve 114 is disposed within the chamber 110 and controls the flow of hydraulic fluid between the chambers 38 and 110. For so much of the structure of the draft-cushioning valve 114 as is necessary to a complete understanding of the present invention, reference may be had to U.S. Pat. No. 3,378,149, which clearly discloses this feature. The draft-cushioning valve 1 14 is operative to achieve draft cushioning only when the primary hydraulic cushioning mechanism 30 is being extended by a draft force from a compressed condition thereof subsequent to receiving a buff force. Under this condition, the resilient draft-cushioning mechanism 60 will cooperate with the hydraulic draft-cushioning valve 114 in order to achieve extremely smooth force transition during application of cushioning in draft. Upon reaching the fully extended condition of the primary hydraulic cushioning mechanism 30, the resilient draft-cushioning mechanism 60 will provide additional cushioning capability in draft to insure against damage to the hydraulic cushioning structure for railway car structure that might otherwise occur by slamming of the cushioning mechanism. This feature also prevents undue wear of the draft-cushioning system of the primary cushioning mechanism therefore providing for extensive service life thereof.

The packing retainer 52 defines a stop surface 116 that engages the oversolid stop 22 when the primary cushioning mechanism 30 is fully collapsed, thereby causing excessive but? forces to be transmitted directly through the outer cylinder structure and through the backstop structural element into the center sill. This feature essentially causes buff forces extremely large magnitude to bypass the inner cylinder, thereby protecting the inner cylinder from excessive deflection.

With reference now to FIGS. 3 and 4, which disclose a modified embodiment of the present invention, it is pointed out that the primary cushioning mechanism disclosed in these figures is substantially identical to that illustrated in FIGS. 1 and 2 with exception of the inner cylinder end cap structure. Reference characters identifying elements of the primary cushioning mechanism of FIGS. 1 and 2 will, therefore, apply to corresponding structure of the primary cushioning mechanism illustrated in FIG, 3 and 4.

A backstop structural element 120 is fixed within the center sill 10 by welding or the like and defines a stop surface 122 that is engaged by the end wall 116 of packing retainer member 152 in the fully compressed condition of the primary hydraulic-cushioning mechanism to prevent damage thereto by excessive buff forces as described hereinabove. The backstop structural element 120 is provided with an integrally formed transverse structural partition 124, having a plurality of apertures 126 and 128 formed therein. Tie bolt members 130 and 132 are threadly secured to an end cap 134 of the inner cylinder 34 and extend through the aperture 126 and 128. Ordinarily four tie bolts will be utilized to secure the draft-cushioning mechanism to the primary cushioning mechanism.

A draft-cushioning mechanism illustrated generally at 136 is defined by a support plate 138 and a retainer plate 140 having apertures through which the tie bolts extend. A plurality of resilient pads 142, separated by metal plates 144, are interposed between the support plate 138 and the retainer plate 140, and are biased into compressive assembly by the tie bolts 130 and 132.

A universal connection is defined by a semispherical convex surface 146 formed on the end cap 134 that mates with a semispherical concave surface 148 formed in a force alignment plate 150. The force alignment plate 150 is provided with apertures receiving the tie bolt members, 130 and 132 to maintain the same and proper position within the backstop structural element 120. In the event the primary cushioning mechanism 30 is slightly misaligned within the center sill structure, the universal connection defined by cooperating surfaces 146 and 148, assure the transfer of evenly distributed forces from the primary cushioning unit to the transverse structural wall 124. This feature effectively eliminates overloading of any specific area of the backstop structural element 120, that might otherwise result in overstressing or other damage. The inner cylinder end cap 134 and the force alignment plate 150 are of larger dimension than the dimension of unit will collapse, causing metering of hydraulicfluid from the outer chamber 40 through the metering orifice 42 to the inner hydraulic chamber 38, under control of the metering pin 34. This fluid transfer will cause the free floating piston 48 to move rearwardly, further compressing the gas disposed within the pneumatic chamber 50. Upon maximum compression, the surface 1'16 of the packing retainer 52 will move into engagement with'the stop surface 122 provided at the forward extremity of the backstop structural element 120. Any further impact forces will be transmitted directly from the outer cylinder to the backstop'structural element and directly into the center sill 12, thereby protecting the inner cylinder against damage by excessively high bufi' forces.

The primary cushioning mechanism-30 may be extended to its 'neutral'position as illustrated in FlG. 3, from the full but? position, either by action of the compressed gas within the pneumatic chamber 50 actingon piston 48 or by draft forces applied to the coupler 84. When draft forces are applied to the coupler, thedraft cushion valve 114 will meter hydraulic fluid from the draft cushioning chamber 110, thereby achieving cushioning in draft as discussed above. The draft force will be exerted through the inner cylinder structure and through the tie bolts 130 and 132, thereby causing the retainer plate 140 to compress the resilient pads 142, therebyachieving further cooperative cushioning in draft. Upon the application of maximum draft loads to the coupler 84, the primary cushioning mechanism will be fully extended to its neutral position and the draft-cushioning mechanism 136 will be fullycompressed,

as illustrated in FIG. 4, thereby allowing shoulders 1'06 and 108 of the outer cylinder end cap 46 to engage stop surfaces 102 and 104 on draft lugs 94 and 96, respectively. Further ap plication of draft forces will be transmitted directly from the coupler to the outer cylinder end cap structure and through the draft lugs 94 and 96, to the center'sill structure, thereby assuring that the draft-cushioning mechanism 136 may not be compressed beyond a predetermined maximum limit that is defined by the FIG. 4' position of both the primary and draficushioning mechanisms.

' In view of the foregoing, it is clearly apparent that we have provided a novel cushioned railway car construction having effectivecushioning capability, both in buff and draft. We have provided a primary oleopneumatic type cushioning mechanism, having cushioning capability, both in bufi and draft and have additionally provided a resilient draft-cushioning mechanism that is active only in draft and supplements the draft-cushioning system of the primary cushioning mechanism to achieve extremely smooth 'force transition. 'lhe' resilient draft-cushioning mechanism provides additional cushioning capability after the primary cushioning mechanism has reached its fully extended condition, thereby preventingthe primary cushioning mechanism'from slamming upon rapid recentering. We have also provided cooperating structure in the center sill and cushioning mechanism that prevents overloading or excessive compression of either the primary 'or draft-cushioning mechanism in the event excessive draft 'or buff forces are applied to the car coupler. These unique features have been obtained even though the structure of the invention has been kept simple in nature providing a structure that is low in cost and reliable in use. Our invention, therefore, is well adapted to attain all of the objects and advantages hereinabove set forth together with other advantages which will become obvious and inherent from a description of the apparatus itself.

It will be understood that certain combinations and subcombinations are of utility and may be employed without reference toother features and combinations. As many possible embodiments may be made of the present invention without imparting from the spirit or scope thereof. it is to be understood that all matters herein set forth or as illustrated in the accompanying drawings may be interpreted as illustrative and not in a limiting sense.

We claim:

1. A railway car having an underframe including a center sill, a transverse structural wall disposed within said center sill and having aperture means formed therein, a primary hydraulic cushioning mechanism disposed within said center sill outwardly of said transversestructural wall and having an end cap adjacent said transverse wall for restraining inward movement of the hydraulic cushioning mechanism upon the application of buff forces, connection means secured to said end cap and extending through said aperture means, a resilient draftcushioning mechanism disposed within said center sill inwardlyof said transverse structuralwalland receiving said connecting means, means retaining said draft-cushioning mechanism in assembly with said connection means and compressing said draft-cushioning mechanism upon the application of draft forces, said draft-cushioning mechanism being unaffected by compression of said primary cushioning mechanism and being operatively compressed only during the application of draft forces to said primary cushioning mechanism.-

2. A railway car as recited in claim 1 draft lug means being disposed adjacent the extremity of said center sill, stop means formed on said cushioning unit and being normally disposed out of contact with said draft lug means, said draft-cushioning mechanism being compressed upon application of predetermined draft forces thereto, whereby said draft stop means will move into contact with said draft lug means.

3. A railway car as set forth in claim 1 said connection means comprising a single bolt extending through said aperture means, said draft-cushioning mechanism comprising at least one resilient pad disposed about said bolt, bearing plate means engaging said pad, said means retaining said draft cushioning mechanism in assembly with said connection means comprising a nut member being threadedly secured to said bolt and biasing said bearing plate into compressive ensaid aperture. means, said draft-cushioning mechanism comprising a plurality of resilient pads disposed between said bolt members, a bearing plate, being received by said bolt means, said means retaining said draft-cushioning mechanism in assembly with said connection means comprising nut members threadedly received by said bolt members and biasing said bearing plate intocompressive engagement with said pads.

5. A railway car as recited in'claim l, a pair of removable draft lugs disposed within said center sill adjacent the extremity thereof, said primary cushioning mechanism being disposed inwardly of said draft lugs and having-draft shoulder means normally disposed out of contact with said draft lugs in the fully extended condition of said primary cushioning mechanism, said draft-cushioning mechanism being compressed upon application of predetermined draft forces thereto whereby said drafi shoulder means will move into contact said draft lugs and result in direct transfer of excessive draft forces into said center sill.

6. A railway car structure as recited in claim 1, said primary cushioning mechanism being an oleopneumatic cushioning mechanism having an outer cylinder, an inner cylinder being received in telescoping relation within-said outer cylinder, an end cap forming a closure for said inner cylinder and having said connecting means provided thereon, a coupler connector forming a closure for said outer cylinder, said coupler connector having stop shoulders fonned thereon, draft lugs carried by said center sill and being normally spaced from said stop shoulders in the fully extended condition of said primary cushioning mechanism, said stop shoulders moving into abutting contact with said draft lugs when said draft-cushioning means is fully compressed.

7. A railway car having an underframe including a center sill, a backstop member disposed within said center sill and defining a transverse partition disposed substantially normal to said center sill, said transverse partition having aperture means formed therethrough, an oleopneumatic cushioning unit disposed within said center sill outwardly of said transverse partition and comprising outer cylinder means and inner cylinder means disposed in telescoping relation, and end cap fonning a closure for said inner cylinder means and having bolt means extending through said aperture means, a draftcushioning mechanism disposed within said center sill inwardly of said transverse partition and being received by said bolt means, means to secure said draft-cushioning mechanism to said bolt means, a coupler connector forming a closures for said outer cylinder, stop shoulder means formed on said coupler connector, draft lugs defined at the extremity of said center sill and being engaged by said shoulder means to limit outward movement of said outer cylinder.

8. A railroad car structure as recited in claim 7, said back stop member also defining oversolid stop means, said outer cylinder moving into engagement with said oversolid stop means in the fully compressed position of said cushioning unit whereby excessive buff forces will bypass said inner cylinder and will be transmitted directly through said outer cylinder into said center sill.

9. A railway car structure as recited in claim 7, said aperture means comprising a single centrally disposed aperture fonned through said partition, said bolt means comprising a single bolt fixed to said inner cylinder end cap and having a threaded extremity, said means to secure said draft-cushioning mechanism to said bolt means comprising a single-threaded nut threadedly secured to said bolt.

10. A railway car structure as recited in claim 9, including universal means to effect even distribution of draft and but? forces through said backstop member.

11. A railway car structure as recited in claim 7, said aperture means comprising a plurality of apertures formed in said partition of said backstop member, a plurality of tie-bolts ex-. tending through said draft-cushioning mechanism and said apertures and being threadedly received by said inner cylinder end cap to secure said draft-cushioning mechanism in assembly with said backstop member.

12. A railway car structure as set forth in claim 7, said draftcushioning mechanism comprising a pair of retainer plates, a plurality of resilient pads interposed between said retainer plates, said bolt means securing said retainer plates and said resilient pads in assembly.

13. A railway car structure as recited in claim 7, said oleopneumatic cushioning unit having cushioning capability in buff and having a draft-cushioning system for cushioning draft forces applied thereto, said drafi-cushioning mechanism cooperating with said draft-cushioning system to achieve smooth force transition and to provide draftcushioning'capability after the draft-cushioning capability of said draftcushioning system has become exhausted.

I! t i I i 

1. A railway car having an underframe including a center sill, a transverse structural wall disposed within said center sill and having aperture means formed therein, a primary hydraulic cushioning mechanism disposed within said center sill outwardly of said transverse structural wall and having an end cap adjacent said transverse wall for restraining inward movement of the hydraulic cushioning mechanism upon the application of buff forces, connection means secured to said end cap and extending through said aperture means, a resilient draft-cushioning mechanism disposed within said center sill inwardly of said transverse structural wall and receiving said connecting means, means retaining said draft-cushioning mechanism in assembly with said connection means and compressing said draft-cushioning mechanism upon the application of draft forces, said draftcushioning mechanism being unaffected by compression of said primary cushioning mechanism and being operatively compressed only during the application of draft forces to said primary cushioning mechanism.
 2. A railway car as recited in claim 1, draft lug means being disposed adjacent the extremity of said center sill, stop means formed on said cushioning unit and being normally disposed out of contact with said draft lug means, said draft-cushioning mechanism being compressed upon application of predetermined draft forces thereto, whereby said draft stop means will move into Contact with said draft lug means.
 3. A railway car as set forth in claim 1, said connection means comprising a single bolt extending through said aperture means, said draft-cushioning mechanism comprising at least one resilient pad disposed about said bolt, bearing plate means engaging said pad, said means retaining said draft-cushioning mechanism in assembly with said connection means comprising a nut member being threadedly secured to said bolt and biasing said bearing plate into compressive engagement with said pad.
 4. A railway car as recited in claim 1, said connection means comprising a plurality of the bolt members extending through said aperture means, said draft-cushioning mechanism comprising a plurality of resilient pads disposed between said bolt members, a bearing plate being received by said bolt means, said means retaining said draft-cushioning mechanism in assembly with said connection means comprising nut members threadedly received by said bolt members and biasing said bearing plate into compressive engagement with said pads.
 5. A railway car as recited in claim 1, a pair of removable draft lugs disposed within said center sill adjacent the extremity thereof, said primary cushioning mechanism being disposed inwardly of said draft lugs and having draft shoulder means normally disposed out of contact with said draft lugs in the fully extended condition of said primary cushioning mechanism, said draft-cushioning mechanism being compressed upon application of predetermined draft forces thereto whereby said draft shoulder means will move into contact with said draft lugs and result in direct transfer of excessive draft forces into said center sill.
 6. A railway car structure as recited in claim 1, said primary cushioning mechanism being an oleopneumatic cushioning mechanism having an outer cylinder, an inner cylinder being received in telescoping relation within said outer cylinder, an end cap forming a closure for said inner cylinder and having said connecting means provided thereon, a coupler connector forming a closure for said outer cylinder, said coupler connector having stop shoulders formed thereon, draft lugs carried by said center sill and being normally spaced from said stop shoulders in the fully extended condition of said primary cushioning mechanism, said stop shoulders moving into abutting contact with said draft lugs when said draft-cushioning means is fully compressed.
 7. A railway car having an underframe including a center sill, a backstop member disposed within said center sill and defining a transverse partition disposed substantially normal to said center sill, said transverse partition having aperture means formed therethrough, an oleopneumatic cushioning unit disposed within said center sill outwardly of said transverse partition and comprising outer cylinder means and inner cylinder means disposed in telescoping relation, an end cap forming a closure for said inner cylinder means and having bolt means extending through said aperture means, a draft-cushioning mechanism disposed within said center sill inwardly of said transverse partition and being received by said bolt means, means to secure said draft-cushioning mechanism to said bolt means, a coupler connector forming a closure for said outer cylinder, stop shoulder means formed on said coupler connector, draft lugs defined at the extremity of said center sill and being engaged by said stop shoulder means to limit outward movement of said outer cylinder.
 8. A railroad car structure as recited in claim 7, said back stop member also defining oversolid stop means, said outer cylinder moving into engagement with said oversolid stop means in the fully compressed position of said cushioning unit whereby excessive buff forces will bypass said inner cylinder and will be transmitted directly through said outer cylinder into said center sill.
 9. A railway car structure as recited in claim 7, said aperture means comprising a single centrally disposed aperture formed thRough said partition, said bolt means comprising a single bolt fixed to said inner cylinder end cap and having a threaded extremity, said means to secure said draft-cushioning mechanism to said bolt means comprising a single-threaded nut threadedly secured to said bolt.
 10. A railway car structure as recited in claim 9, including universal means to effect even distribution of draft and buff forces through said backstop member.
 11. A railway car structure as recited in claim 7, said aperture means comprising a plurality of apertures formed in said partition of said backstop member, a plurality of tie-bolts extending through said draft-cushioning mechanism and said apertures and being threadedly received by said inner cylinder end cap to secure said draft-cushioning mechanism in assembly with said backstop member.
 12. A railway car structure as set forth in claim 7, said draft-cushioning mechanism comprising a pair of retainer plates, a plurality of resilient pads interposed between said retainer plates, said bolt means securing said retainer plates and said resilient pads in assembly.
 13. A railway car structure as recited in claim 7, said oleopneumatic cushioning unit having cushioning capability in buff and having a draft-cushioning system for cushioning draft forces applied thereto, said draft-cushioning mechanism cooperating with said draft-cushioning system to achieve smooth force transition and to provide draft-cushioning capability after the draft-cushioning capability of said draft-cushioning system has become exhausted. 